The present invention relates to a mandrel for use in winding a ball of yarn, thread or the like, in particular to an improved mandrel for use in high speed ball winding machines for hand knitting yarns.
Mandrels for use in automatic ball winding machines are well known, as reference to Swiss Patent No. 544,716, British Patent No. 172,782 and German Patent Nos. 1,061,668 and 1,074,458 will show. Such mandrels generally consist of a collapsible frame comprising several links radially spaced about a central axis which are connected together to form a trapeze when opened. During the winding process the yarn is laid on the open frame and once the winding is complete the mandrel is closed thereby reducing the diameter and allowing the ball that has been wound to be removed.
In winding yarns, particularly yarns which are brushed or of the mohair type having small fibers extending from the main body of the yarn, the conventional type of mandrel has a decided disadvantage in that the fibers tend to get trapped between the various joints of the links. As a result, the inner part of the wound ball snags on the collapsed frame and is pulled out from the remainder when the ball is removed or doffed from the mandrel.
It has been attempted to avoid this problem by equipping the known mandrels with a fabric bag covering the various joints. This solution has its limitations in that the friction between the fabric and the yarn of the ball, under winding tension, still contributes to the snagging of the ball and continues to result in the inner part of the ball being pulled out while being doffed. Furthermore, the life of such a bag is very small due to the mechanical action of opening and closing the mandrel, and the friction of removing the wound ball. Considerable down time therefore occurs in order to periodically inspect the fabric bag, and for its replacement.